This patent application claims priority based on a Japanese patent application, H11-282175 filed on Oct. 1st, 1999, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a testing apparatus for testing electric parts. More particularly, the present invention relates to pin electronics that input and output signal from and to input/output pins of the electric parts.
2. Description of the Related Art
FIG. 1 shows a block diagram of a conventional testing apparatus 100. The testing apparatus 100 judges whether an electronic part 16 is normal or not by applying a predetermined signal on the electronic part 16. For example, the electronic part 16 is part that performs a predetermined action according to an electric current or a voltage. The electronic part 16 includes not only a semiconductor part constructed by an active element such as an IC (Integrated circuit) or an LSI (Large-Scale Integrated circuit) but also a passive element, and several kinds of sensors. The electronic part 16 further includes a part that accommodates the above mentioned parts, which are coupled with each other, into one package or a part such as a breadboard that realize a predetermined function by mounting the above mentioned parts on a printed substrate.
On the transmission path of a signal from an input/output pin of the electronic part 16 to a driver 20, the testing apparatus 100 has a programmable load 24, a driver 20, a clamp unit 26, and a switch 28. The programmable load 24 provides a predetermined load to the electronic part 16 according to the output value of the electronic part 16. The clamp unit 26 controls a voltage at the input/output pin of the electronic part 16 in order to protect the driver 20, the judging unit 22 and the programmable load 24. The switch 28 connects the electronic part 16 and a DC measuring unit 14 when performing a voltage applying current measuring test, which applies a voltage on the electronic part 16 to measure a current, or performing an electric current applying voltage measuring test, which applies an electric current on the electronic part 16 to measure a voltage.
If the DC measuring unit 14 is provided for all of the input/output pins of the electronic part 16, the magnitude of the circuit becomes large, and thus the DC measuring unit 14 is not provided for all the input/output pins of the electronic part 16. Therefore, the voltage applying current measuring test or the current applying voltage measuring test could not be performed at the same time on the input/output pin of the electronic part 16. Furthermore, a floating capacity increases by providing the DC measuring unit 14 on the transmission path, thus causing a decrease of measuring accuracy at the time of AC testing.
Therefore, it is an object of the present invention to provide a pin electronics and a testing apparatus, which overcomes the above issues in the related art. This object is achieved by combinations described in the independent claims. The dependent claims define further advantageous and exemplary combinations of the present invention.
According to the first aspect of the present invention, a pin electronics, which inputs and outputs signal from and to an input/output pin of an electric part, provided in a testing apparatus that tests the electric part comprises: a current source which outputs desired electric current; a first voltage generator which generates a desired voltage; and a diode bridge, which is connected to each of the current source, the first voltage generator, and the input/output pin of the electric part, that provides the desired electric current to the electric part and provides the desired voltage to the electric part; wherein: the first voltage generator has a current measuring unit that measures an electric current, which is input from the first voltage generator to the diode bridge.
The current source may have a first current source that outputs the desired electric current to the diode bridge and a second current source that inputs the desired electric current from the diode bridge; and the pin electronics may further comprise: a control unit that controls the first current source to output a predetermined electric current and controls the second current source to input the predetermined electric current from the diode bridge when measuring an electric current, which is input to the electric part, by applying a predetermined voltage on the input/output pin. The first voltage generator may be provided corresponding to each of the input/output pins of the electric part.
The pin electronics may further comprise: a clamp unit that compensates for an output value of the electric part; and a comparator, which judges an output voltage output from the electric part; wherein: the clamp unit includes: a second voltage generator which generates a voltage to be provided to the electric part; a current generator which generates desired current; a switch that selects a voltage, which is generated by the second voltage generator, o, a the desired electric current generated by the current generator to be provided to the electric part; and the control unit controls the switch to select the current generator to provide the desired electric current to the electric part and controls the comparator to judge the output voltage when measuring the output voltage by applying the desired electric current on the electric part.
The control unit may stop provision of an electric current provided from the first current-source and the second current source to the diode bridge, when measuring the output voltage by applying the desired electric current on the electric part. The reference voltage source may provide a reference voltage whilst changing the reference voltage one after another, and the comparator compares the reference voltage, which is changed one after another, with the output voltage and judges that the output voltage has a voltage value equal to a voltage value of the reference voltage when the reference voltage matches the output voltage, when measuring the output voltage by applying the desired electric current on the electric part.
According to the second aspect of the present invention, a pin electronics, which inputs and outputs signal from and to an input/output pin of an electric part, provided in a testing apparatus that tests the electric part; comprises: a clamp unit which compensates for an output value of the electric part; wherein: the clamp unit includes: a voltage generator which generates a voltage to be provided to the electric part; a current generator which generates desired current; a switch that selects to provide a voltage, which is generated by the voltage generator, to the electric part or to provide the desired electric current generated by the current generator to the electric part; and the pin electronics further comprises: a comparator, which judges an output voltage output from the electric part; and a control unit that controls the switch to select the current generator to provide the desired electric current to the electric part and controls the comparator to judge the output voltage when measuring the output voltage by applying the desired electric current on the electric part.
According to the third aspect of the present invention, a testing apparatus for testing whether an electric part is normal or not, comprises: a pattern generator that generates a test pattern to be applied to the electric part and an expectation value, which is to be output when the electric part is normal; a pin electronics that outputs the test pattern to the electric part and inputs an output value of the electric part; a comparison unit that compares the expectation value and the output value, which is provided via the pin electronics, and judges whether the electronic part is normal or not; wherein: the pin electronics may have: a current source that outputs desired current; a voltage generator that generates desired voltage; and a diode bridge, which is connected to each of the current source, the voltage generator, and the input/output pin of the electric part, that provides the desired electric current to the electric part and provides the desired voltage to the electric part; and the voltage generator has a current measuring unit that measures an electric current, which is input from the voltage generator to the diode bridge.
According to the fourth aspect of the present invention, a testing apparatus for testing whether an electric part is normal or not, comprises: a pattern generator that generates a test pattern to be applied to the electric part and an expectation value to be output when the electric parts is normal; a pin electronics that outputs the test pattern to the electric part and inputs an output value of the electric part; a comparison unit that compares the expectation value and the output value, which is provided via the pin electronics, and judges whether the electronic part is normal or not; wherein: the pin electronics has: a clamp unit which compensates for an output value of the electric part; and a comparator, which judges an output voltage output from the electric part; wherein: the clamp unit includes: a voltage generator which generates a voltage to be provided to the electric part; a current generator which generates a desired current; a switch that selects whether to provide a voltage, which is generated by the voltage generator, to the electric part or to provide the desired electric current generated by the current generator to the electric part; and the testing apparatus further comprising a control unit that controls the switch to select the current generator to provide the desired electric current to the electric part and controls the comparator to judge the output voltage when measuring the output voltage by applying the desired electric current on the electric part.
This summary of the invention does not necessarily describe all necessary features of the present invention. The present invention may also be a sub-combination of the above described features. The above and other features and advantages of the present invention will become more apparent from the following description of embodiments taken in conjunction with the accompanying drawings.